Preliminary validation study of the WHO quality of life (WHOQOL) scales for people with spinal cord injury in Mainland China

Abstract

Objective

To validate the WHOQOL Scales (WHOQOL-BREF and WHOQOL-DIS module) for people with spinal cord injury in Mainland China.

Design

Cross-sectional study.

Setting

Shanghai Sunshine Rehabilitation Center.

Participants

249 adults with SCI who were admitted to a rehabilitation training program between 2017 and 2019.

Interventions

Not applicable.

Methods

Questionnaires about personal and injury characteristics, the WHOQOL Scales, global QOL, Zung Self-Rating Anxiety/Depression Scale (SAS/SDS), and Community Integration Questionnaire (CIQ) were administrated. Floor and ceiling effects, reliability, and validity analyses were tested.

Results

The 8 domains of the WHOQOL Scales showed no floor or ceiling effects. Cronbach alpha values of the WHOQOL-BREF and the WHOQOL-DIS were 0.93 and 0.78, respectively. Test-retest reliability was good for the WHOQOL Scales. Satisfactory criterion-related validity was shown by the correlation analysis among the WHOQOL Scales, SAS/SDS, CIQ, and global QOL. Good item-domain correlations (>0.50) were found for 38 items of the 39-item WHOQOL Scales, excepting the “impact of disability” (0.48) of the WHOQOL-DIS. Confirmatory Factor Analysis (CFA) supported a construct of the WHOQOL-DIS as made of four domains: autonomy, social inclusion, social activities, and discrimination. CFI and RMSEA values were 0.91 and 0.07, respectively, for the four-domain structure WHOQOL-DIS, with a higher-order factor. WHOQOL-BREF domains and WHOQOL-DIS scores showed the predicted pattern among a priori known groups.

Conclusion

The WHOQOL Scales are valid and reliable, and they can be used to measure QOL in people with SCI in China. We suggest the WHOQOL-DIS be analyzed as one general item constituting a single 12-item domain.

Introduction

Spinal cord injury (SCI) is damage to the spinal cord resulting from traumatic or non-traumatic causes.¹ As a permanent disability, SCI results in individuals’ substantial economic and emotional burdens, lower quality of life (QOL) than the general population or population norms, and socio-economic costs in terms of healthcare treatments, rehabilitation, and lost productivity.² Until now a nationwide database of SCIs has not been set up in Mainland China. By reference to the reported global prevalence of traumatic SCI,³ there are an estimated 0.33–1.41 million people with SCI living in Mainland China. Given an increased life-span for all Chinese citizens, QOL is regarded as the key outcome of SCI rehabilitation⁴ and has been a concern not only of people with SCI but also of healthcare professionals.⁵ A QOL measurement instrument for people with SCI is essential in medical practice, research, policy making, and assessing the effectiveness of different treatments.⁶ To date, many QOL outcome measures intended for use on generic populations have been used in studies assessing the QOL of people with SCI. The commonly used patient reported outcomes (PROs) measures are the Short-Form 36, Craig Handicap Assessment and Reporting Technique, Short-Form 12, Satisfaction with Life Scale, World Health Organization Quality of Life assessment (WHOQOL-100 and its abbreviated version: WHOQOL-BREF), global QOL questions, and International Spinal Cord Injury Quality of Life Basic Data Set.^7,8 The existing SCI-specific instruments are the Life Situation Questionnaire or its revised form, the Spinal Cord Injury Quality of Life Questionnaire (SCI QL-23) or SCI-QOL measurement system.^9–11 However, the SCI-specific instruments are suggested to be used in combination with generic measures.¹²

The WHOQOL-100 and WHOQOL-BREF are intended as generic QOL tools for use with people across varying disease types, severities of illness, and cultural subgroups,^13,14 and they are currently being validated in field studies involving at least 30 languages.¹⁵ The Chinese version of the WHOQOL-100 and the WHOQOL-BREF were introduced into Mainland China in 1998.¹⁶ The Mainland Chinese version of the WHOQOL-BREF consists of 28 items; 26 standard items from the original WHOQOL-BREF supplemented by two items that are unique to China.¹⁷ The add-on module, known as the WHOQOL-DIS, was developed before 2010 to assess the QOL of adults with physical or intellectual disabilities.¹⁸

The WHOQOL-BREF is an appropriate generic health-related QOL measure for people with SCI,¹⁹ but there exist studies that have not successfully validated the tool.²⁰ The validity studies of the WHOQOL-BREF and/or the WHOQOL-DIS module in the SCI population have been made in Singapore,²¹ Republic of Korea,²² Hong Kong, and Taiwan.^23,24 However, since Mainland China is a developing area compared with those developed regions, there is a need to validate the WHOQOL Scales (the WHOQOL-BREF and the WHOQOL-DIS module) for people with SCI in Mainland China. The WHOQOL Scales for people with physical disabilities has been validated in 1,853 persons with physical disability in Mainland China,²⁵ but the specific disabilities of the participants were not reported, and we do not know whether or not it included people with SCI. The WHOQOL-BREF had been used in relevant studies on people with SCI in Mainland China.^26–29 Sun et al. reported the reliability and validity of the WHOQOL-100 in 209 persons with at least 2-year SCI (age range:18–72 years; region distribution not provided) in Mainland China,³⁰ and it was recommended for use in people with SCI in that country. In conclusion, little research has examined the reliability and validity of the WHOQOL-BREF and the WHOQOL-DIS module in people with SCI in Mainland China. The objective of this study was to investigate the internal consistency, test-retest reliability, criterion-related validity, and construct validity of the WHOQOL Scales in adults with SCI.

Materials and methods

Participants and procedures

The “Hope House” project that run by the Department of Occupational and Social Rehabilitation in Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center, SSRC) provided the participants. The project is a government-supported program that provides specialized, institution-based rehabilitation (SIBR) training for people from Shanghai and other provinces who have SCI and who need to improve their QOL and reintegrate into their communities. There exist two application channels. The main channel is described as follows. First, people with SCI from the surrounding communities apply to the Shanghai Disabled Persons’ Federation (SDPF) at the street (town) level for training openings. After examination and verification by the SDPF, the “Hope House” project is responsible for providing inpatient rehab-training services to those who meet the requirements set by the Federation. A second application channel is open to patients with SCI who have completed post-acute care and rehabilitation in the Department of SCI Rehabilitation in the SSRC. They can directly apply to the Hope House project for training openings before discharge, and the project itself is responsible for examination and verification. After their first rehabilitation, people with SCI who are younger than age 70 could apply for readmission, if they wish, and be enrolled in the second period of rehabilitation within 2 years. In this study, the participants who signed informed consents and met eligibility requirements completed all surveys within two days after admission to Hope House, while they were inpatient at the rehab facility.

Inclusion criteria for participants in this study were as follows: (a) SCI, (b) aged between 18 and 70 years old and (c) had lived with the injury for at least half year. Adults with cognitive impairment or on their second admission for rehabilitation were excluded from the data analysis. The study sample included 249 adults with a first admission to the SSRC between 2017 and 2019 (2017: 139 persons; 2018: 50 persons; 2019: 60 persons); 205 (82.2%) were from Shanghai, and 44 were from other provinces. Of the 139 participants in 2017, 62 completed the WHOQOL Scales for the test-retest reliability, and the interval between test and retest ranged from 7 to 10 days to control for maturational effects. The wording of the written informed consent (WIC) form stressed the possibility of dropping out of the study at any time if desired. This study was approved by the ethics committee of the School of Public Health at Fudan University in Shanghai, China.

Data and measurement

The study’s design was cross-sectional. The data was collected by PROs. Data integrity was checked when we collected the questionnaires; missing values due to unintentional omission or misunderstanding were filled in immediately by the respondents. Personal and injury characteristics included the participants’ sex, age, region, educational background, marital status, employment, year of injury, cause of injury, level of injury, and its severity. Marital status was classified as unmarried, married, divorced, or widowed. Levels of lesion were categorized into cervical, thoracic, and lumbosacral. The causes of injury were classified as traumatic and disease-induced. The severity of the injury was described as either complete or incomplete. Because the Hope House project was initiated in 2009, the year of injury was classified as before 2009 and after 2009.

WHOQOL Scales

QOL was assessed with the Chinese version of the WHOQOL Scales for people with physical disability (PD).²⁵ The individuals were asked to reflect on the last 4 weeks, following the WHO’s suggestion for chronic conditions.¹⁵ The first 2 items of the WHOQOL-BREF evaluated general QOL and health, while the remaining 24 items could be classified into four domains: physical (7 items: 3–4, 10, and 15–18), psychological (6 items: 5–7, 11, 19, and 26), social relationships (3 items: 20–22), and environment (8 items: 8–9, 12–14 and 23–25). They were all rated on a five-point scale. To maintain the comparability with the standard WHOQOL-BREF, two additional Chinese-specific items were not used in this study.¹⁷ The WHOQOL-DIS module is comprised of 12 items plus one general item that assesses the overall impact of disability. According to a previous validity study in people with physical disabilities in Mainland China,²⁵ those 12 items made up 4 domains: discrimination (3 items: 28–30), autonomy (3 items: 31–33), social inclusion (3 items: 34–36), and social activities (3 items: 37–39). Responses to each item were measured on a scale from 1 (not at all) to 5 (very much).

Global QOL

The global QOL recorded the respondent’s self-rated health on a scale numbered from 0 to 100.³¹ This information was used as a quantitative measure of overall self-rated health status at the day of investigation, with high scores indicating better health.

Anxiety and depression

Anxiety/depression was measured using the Zung Self-Rating Anxiety/Depression Scale (SAS/SDS).^32,33 The raw score (with a potential range of 20–80) multiplied by 1.25 was converted to an index score ranging from 25 to 100,³³ with higher scores indicating more severe anxiety/depression.

Community integration questionnaire (CIQ)

The CIQ had a total of 15 items across three domains: home integration, social integration, and productivity.³⁴ Total score from the CIQ ranged from 0 to 29. Higher scores indicated better functioning in terms of integration and productivity.

Floor and ceiling effects

The frequency of the lowest or highest possible score for an item, a domain, or a scale was considered as the floor or the ceiling. The floor or ceiling effects were present if the percentages were over 15%,³⁵ which limited the range of data reported by the instrument and reduced variability in the gathered data.

Reliability analyses

Internal consistency analyses (Cronbach’s alpha) and test-retest reliability were done in the reliability analyses, and Cronbach’s alpha > 0.7 was an acceptable level of good internal consistency.³⁶ Paired-samples T test was used for the comparison of mean scores between the test and retest results, and Pearson’s correlation and Kappa coefficients were analyzed, with a Kappa value of 0.00–0.19 considered to be low, 0.20–0.59 moderate, and 0.60–1.00 high.³⁷ Pearson’s correlation >0.7 was regarded as high test-retest consistency.³⁸

Validity analyses

Validity analyses were tested by criterion-related validity and construct validity. To assess criterion-related validity, the associations of the items (impact of disability, and general QOL and health) and the domains of the WHOQOL Scales with the SAS, the SDS, the CIQ, and the VAS scales were examined. Pearson correlations were used to explore the association. Correlations between the WHOQOL-BREF/WHOQOL-DIS domains/items and the SAS/SDS were expected to be negative, while correlations with the CIQ/VAS were expected to be positive. Construct validity was tested by three different approaches: Confirmatory Factor Analysis (CFA), convergent validity, and the known-groups method. The WHOQOL-DIS’s proper structure, including sub-domains, was identified by CFA and was compared to the factorial structure of the original global WHOQOL-DIS. Comparative Fit Index (CFI) and Root Mean Square Error of Approximation (RMSEA) were calculated. For adequate fit, CFI was expected to be higher than 0.9 and RMSEA lower than 0.08.³⁹ Item-domain correlation analyses were a method to show convergent validity, with the correlation coefficients ≥0.5 showing good validity, 0.3–0.5 moderate, and < 0.3 low.⁴⁰ The variables such as sex, age, education background, employment status, general health perception, and the negative impact of disability on the individual’s life were used in the known-groups validity analyses. These selected characteristics were previously reported to be significantly correlated with QOL among people with SCI.⁴¹ It was expected that people who were younger, were female, were employed, had higher educational background, had satisfactory health, and felt fewer bad effects of disability on his/her daily life would have significantly higher scores compared with their counterparts. Comparison of two means was used in parametric analysis.

Scoring and statistical analysis

For each of the four domains of the WHOQOL-BREF, summary scores were calculated and ranged from 4 to 20, with low scores indicating poor QOL. The 12-item WHOQOL-DIS module scores were calculated manually (total scores = 12–60), and a higher score reflected a higher QOL.

In this study, the descriptive analysis included the counts and percentages of the categorical variables, as well as the means of all scale variables with standard deviations (SDs) and ranges. The percentages of the missing value were calculated to assess acceptability. All statistical tests were two-sided with a significant P-value < 0.05. The alpha level was set at α< 0.05, with a Holm–Bonferroni adjustment made for multiple comparisons in known groups. If the p-value of the normality test (Kolmogorov–Smirnov test) was < = 0.05, Spearman’s rho correlations were calculated in nonparametric analysis. CFA using maximum likelihood estimation was carried out in Amos 21.0, and the Statistical Package for Social Sciences for Windows (SPSS for Windows 13.0, SPSS Inc., Chicago, IL, USA) was used to perform all the analyses.

Results

Social demographics and general injury characteristics of people with SCI

The demographic and injury characteristics of the participants and sub-portions for test-retest reliability are presented in Table 1. The mean (SD) age on admission was 48.3 (13.7) years. The mean (SD) age at injury was 35.6 (16.6) years, ranging from 0 (congenital) to 67 years. The median time from injury to the beginning of the rehabilitation training at the SSRC was 6 years, ranging from 6 months to 61 years.

Table 1.

Personal and injury characteristics of 249 participants with SCI and 62 sub-portions for test-retest reliability.

Category variables		Total		Sub-portion
		N	%	N	%
Sex	Male	165	66.3	39	62.9
	Female	84	33.7	23	37.1
Education#	Junior high school or below	114	45.8	26	41.9
	Senior high school/secondary vocational school	74	29.7	19	30.6
	Junior or regular college	61	24.5	17	27.4
Marital status#	Unmarried	66	26.5	23	37.1
	Married	152	61.0	31	50.0
	Divorced or widowed	31	12.5	8	12.9
Employment	Employed	31	12.5	16	25.8
	Unemployed	132	53.0	27	43.5
	Retired	86	34.5	19	30.6
Year of injury	1958–2008	108	43.4	41	66.1
	2009–2019	141	56.6	21	33.9
Levels of injury	Cervical cord	78	31.3	7	11.3
	Thoracic cord	123	49.4	38	61.3
	Lumbosacral cord	48	19.3	17	27.4
Etiology	Traumatic	196	78.7	47	75.8
	Disease	53	21.3	15	24.2
Severity	Complete	149	59.8	41	66.1
	Incomplete	100	40.2	21	33.9

#: on admission.

Floor and ceiling effects

Data quality was satisfactory in view of there being no missing values, and the WHOQOL-BREF and four domains of the WHOQOL-DIS module showed no floor or ceiling effects (Table 2). The floor effect existed in the overall impact of disability (25.3% > 15%).

Table 2.

Descriptives, floor and ceiling effects, and internal consistency of the WHOQOL-BREF and WHOQOL-DIS.

Domains/Items	No. of items	Descriptives		Floor (%)	Ceiling (%)	Cronbach’s α
		Mean	SD
Overall QOL*	1	2.99	1.05	11.2	7.2	—
Overall health*	1	2.62	1.01	14.5	2.4	—
Physical*	7	11.55	2.92	1.2	0.4	0.82
Psychological*	6	13.02	2.86	0.4	0.4	0.85
Social*	3	12.40	2.73	0.0	0.4	0.59
Environmental*	8	12.42	2.64	0.4	0.0	0.83
Impact of disability#	1	2.19	0.96	25.3	1.2	—
Discrimination#	3	2.47	0.77	1.6	0.4	0.57
Autonomy#	3	3.48	0.86	2.0	4.0	0.75
Social inclusion#	3	3.63	0.59	0.0	1.6	0.66
Social activities#	3	3.32	0.68	1.2	1.6	0.71
12-item WHOQOL-DIS	12	38.71	6.11	0.0	0.4	0.78

*: WHOQOL-BREF; #: WHOQOL-DIS.

Reliability

Internal consistency was satisfactory (Cronbach’s α > 0.70) for three domains of the WHOQOL-BREF, excepting only the social domain (0.59) (Table 2). For the WHOQOL-DIS module, two domains (i.e. autonomy and social activities) and the 12-item WHOQOL-DIS showed good internal consistency, except for the discrimination (0.57) and inclusion (0.66) domains. As shown in Table 3, test-retest reliability was good for the two general items and 3 domains of the WHOQOL-BREF and the social activities domain of the WHOQOL-DIS. However, the correlation coefficients of the social domain (0.67) of the WHOQOL-BREF and those of three domains (0.63–0.67) and one general item (0.32) of the WHOQOL-DIS module were below the acceptable level (< 0.7). Thirty-eight items out of the 39-item WHOQOL Scales showed moderate consistency (0.20–0.59) as measured by Kappa value, and item 7 (thinking, 0.63) in the psychological domain had high consistency.

Table 3.

Test-retest reliability of the WHOQOL-BREF and WHOQOL-DIS domains and total scores (N = 62).

Domains/Items	T1		T2		Correlation	Kappa range
	Mean	Quartile	Mean	Quartile
Overall QOLa	3.24	3–4	3.35*	3–4	0.75#	0.57
Overall healtha	2.85	2–3	2.77*	2–3	0.73#	0.49
Physicala	12.52	9.71–14.43	12.42*	10.29–14.86	0.82**	0.33–0.57
Psychologicala	14.17	12.67–16.00	14.04*	12.00–16.00	0.81**	0.20–0.63
Sociala	13.08	11.67–14.67	13.14*	12.00–14.67	0.67#	0.36–0.47
Environmentala	13.51	12.00–15.13	13.52*	12.00–15.25	0.81**	0.35–0.56
Impact of disabilityb	2.45	2–3	2.35*	2–3	0.32#	0.58
Discriminationb	2.36	1.67–2.67	2.37*	2–2.67	0.66#	0.31–0.51
Autonomyb	3.75	3.00–4.08	3.73*	3–4.08	0.63#	0.31–0.42
Social inclusionb	3.69	3.00–4.00	3.68*	3.00–4.00	0.67#	0.44–0.54
Social activitiesb	3.56	3.00–4.00	3.48*	3.00–4.00	0.73#	0.42–0.57
12-item WHOQOL-DIS	40.10	36.00–43.25	39.81*	36.00–42.00	0.76**	0.31–0.57

a: WHOQOL-BREF; b: WHOQOL-DIS; T1: First time test; T2: Retest; *: P > 0.05 (compared to T1). **: Pearson’s correlation; #: Spearman’s Rho; correlation coefficients equal or above 0.70 show good reliability.

Criterion-related validity

The criterion-related validity results of SAS, SDS, CIQ, and VAS are shown in Table 4. The scores of 3 items and 8 domains of the WHOQOL Scales were significantly negatively correlated with both SAS and SDS except for the discrimination domain, which was not correlated to SDS. Meanwhile, the scores of 3 items and 8 domains of the WHOQOL Scales were significantly positively correlated with CIQ and VAS, as expected, except for the discrimination domain, which showed no significant correlation with VAS.

Table 4.

Correlation analysis of the WHOQOL Scales and SAS, SDS, CIQ, and VAS.

Domains/Items	SAS	SDS	CIQ	VAS
Overall QOL	–0.49	–0.48	0.36	0.39
Overall health	–0.50	–0.48	0.34	0.44
Physical	–0.61	–0.54	0.46	0.43
Psychological	–0.56	–0.57	0.36	0.40
Social	–0.25	–0.31	0.24	0.21
Environmental	–0.53	–0.48	0.37	0.35
Impact of disability	–0.45	–0.39	0.32	0.30
Discrimination	–0.14*	–0.08**	0.16*	–0.001**
Autonomy	–0.37	–0.27	0.41	0.31
Social inclusion	–0.38	–0.30	0.16	0.18*
Social activities	–0.34	–0.34	0.32	0.25
12-item WHOQOL-DIS	–0.45	–0.36	0.41	0.24

SAS/SDS: Zung Self-Rating Anxiety/Depression Scale; CIQ: Community Integration Questionnaire; VAS: Visual Analogue Scale; *: P < 0.05; **: P > 0.05; other correlations: P < 0.01.

CFA

The three sub-domain structure model fit better (CFI = 0.75, RMSEA = 0.12) than four sub-domains (CFI = 0.70, RMSEA = 0.13) and a single domain (CFI = 0.59, RMSEA = 0.15) of the WHOQOL-DIS. However, the fit could be improved when a higher-order factor was included, and the best fit existed in the four-domain structure model (Fig. 1) (CFI = 0.91, RMSEA = 0.07).

Figure 1.

Best fitting CFA model for the WHOQOL-DIS module.

Convergent validity

Convergent validity was tested by item-domain correlation analysis (Table 5). Good item–domain correlations (>0.50) were found for 38 items of the WHOQOL Scales, except for “impact of disability” within the WHOQOL-DIS module, which had a moderate correlation (0.48).

Table 5.

Item-domain correlations of the WHOQOL-BREF and DIS modules in Chinese participants with SCI.

Domains/Items	Item-domain correlation* range	Domains/Items	Item-domain correlation* range
Overall QOL	0.69a	Impact of disability	0.48b
Overall health	0.59a	Discrimination	0.64–0.76
Physical	0.61–0.78	Autonomy	0.78–0.83
Psychological	0.62–0.84	Social inclusion	0.74–0.81
Social	0.69–0.81	Social activities	0.77–0.78
Environmental	0.59–0.75	WHOQOL-DIS	0.48–0.83
WHOQOL-BREF	0.59–0.84

*: All the P < 0.01; a: Correlation coefficients with total score 24-item WHOQOL-BREF; b: Correlation coefficient with total score 12-item WHOQOL-DIS.

Known-Groups validity

Table 6 shows that females have higher mean domain scores than males, except for the psychological domain, The employed people with SCI had a better QOL in all domains than that of the unemployed. The self-rated general health status was positively associated with the domains, showing higher QOL in participants who perceived themselves to be healthy compared with those who thought of themselves as ill. Participants who reported no to a moderately negative effect of disability on their lives had a higher QOL. However, age and educational levels might not be predictors of QOL for persons with SCI in Mainland China (Table 6).

Table 6.

Mean differences of the WHOQOL-BREF domains and the WHOQOL-DIS in known groups.

Variables	Physical	Psychological	Social	Environmental	12-item WHOQOL-DIS
Sex:
Male	11.2 (3.0§)*	12.8 (2.9)#	11.9 (2.5)**	12.1 (2.6)*	38.1 (6.1)*
Female	12.2 (2.6)	13.4 (2.7)	13.4 (2.9)	13.0 (2.7)	40.0 (5.9)
Age (years):
<50	12.0 (2.7)#	13.2 (2.6)#	12.3 (2.8)#	12.7 (2.6)#	39.6 (6.1)#
≥ 50	11.2 (3.0)	12.8 (3.1)	12.5 (2.7)	12.1 (2.6)	38.0 (6.1)
Education:
Low	11.3 (2.9)#	12.8 (2.8)#	12.1 (2.5)#	12.2 (2.5)#	38.2 (6.1)#
Medium-high	11.7 (3.0)	13.2 (2.9)	12.6 (2.9)	12.6 (2.8)	39.1 (6.1)
Employment:
Employed	12.7 (2.2)*	14.2 (2.7)*	13.5 (3.3)*	14.0 (2.7)**	41.7 (5.4)*
Unemployed	11.4 (3.0)	12.9 (2.8)	12.3 (2.6)	12.2 (2.6)	38.3 (6.1)
Overall health:
Very dissatisfied to moderate	11.0 (2.8)**	12.5 (2.8)**	12.0 (2.6)**	12.0 (2.6)**	38.0 (6.0)**
Good to very good	14.0(2.2)	15.1 (2.1)	13.9 (2.7)	14.1 (2.3)	41.7 (5.7)
Negative effect on life:
Nothing to moderate	13.4 (2.4)**	14.4 (2.5)**	13.3 (2.9)**	13.6 (2.4)**	42.2 (5.9)**
Mostly to totally	10.7 (2.7)	12.4 (2.8)	12.0 (2.5)	11.8 (2.5)	37.0 (5.5)

P was computed by the Holm-Bonferroni method. **: P < 0.01;*: P ≤ 0.05; #: P > 0.05; §: Standard deviation.

Discussion

This study provides an initial validity analysis of the WHOQOL Scales (simplified Chinese version) in adult people with SCI in Mainland China. Our results suggest that the WHOQOL Scales is a reliable QOL measurement for people with SCI in Mainland China.

As a developing country, China has limited resources to provide rehabilitation services to people with SCI. They can receive some hospital-based rehabilitation services after the injury onset, then they return home with limited information and skills necessary for maintaining optimal health and well-being. Before 2009, most people with SCI did not have access to any services after acute care hospital discharge. In 2009, however, the China Association of Persons with Physical Disability, a government-supported national organization, started community co-op centers called “Halfway Houses (changed to “Hope Houses” in 2017)” for individuals with SCI in four provinces: Shanghai, Zhejiang, Henan, and Guangxi. Hope Houses are the platform for community-based rehabilitation (CBR) for individuals with SCI. The Hope House project was initiated as a part of the SSRC. Due to limited space, no more than 20 people with SCI are enrolled in each SSRC rehabilitation program, which lasts between 30 and 45 days. Given the great number of people with SCI living in Mainland China, the need for SCI rehab services is high, while the service capacity of the Hope House program is very small. This is why someone with 61 years of SCI history was enrolled to attend the first SIBR training in the SSRC.

Consistent with a previous study in Spain,⁴² the domains of the WHOQOL-BREF and WHOQOL-DIS demonstrated no floor or ceiling effects. Jang et al.²⁴ reported there were no floor or ceiling effects for the 4 domains of the WHOQOL-BREF in Taiwanese persons with SCI. However, this study found a floor effect in one item of the WHOQOL-DIS (overall impact of disability), which suggested the item was not suitable to assess the overall disability effect on the lives of people with SCI in Mainland China.

In view of Alpha values, test-retest reliability, and Kappa value, the WHOQOL-BREF and WHOQOL-DIS module showed acceptable reliability in people with SCI in Mainland China. Alpha values of three domains, excepting only the social domain (0.59), of the WHOQOL-BREF were good (α > 0.7). Similar Alpha values for the WHOQOL-BREF have been found in previous studies,^{13,19,24,25,42} and the satisfactory internal consistency of the WHOQOL-DIS has also been seen in studies from Spain (0.81) and 14 global centers (0.85).^18,42 Nevertheless, the social domain of the WHOQOL-BREF, and the discrimination and social inclusion domains of the WHOQOL-DIS, showed unacceptable Alpha values (< 0.7) in our study. This lower value is expected and acceptable, because Cronbach alpha is highly influenced by the number of items in each factor,⁴³ and four-item scores would generally be regarded as the minimum required for assessing the internal consistency of a scale.⁴⁴

The minimum value of test-retest reliabilities was 0.67 (correlation coefficient) for the social domain of the WHOQOL-BREF, however, there was a lower value in the physical health domain (0.66) in a study made by the WHO.⁴⁵ The correlation coefficients that were less than 0.7 showed in three domains of the WHOQOL-DIS module, and the lowest value was seen in the general item (impact of disability: 0.32), which may indicate that the item should not be used independently due to its low test-retest reliability.⁴⁶ Consistent with Tian’s previous study in people with disabilities in China,²⁵ the vast majority of kappa values for the WHOQOL Scales were moderate at the item level. The studies from Korea and the WHO found the three-factor model was the best fit;^18,22 however, our study showed the four-factor model was the best fit, and Fu reported these same results.⁴⁷ In general, the results of our reliability and CFA analysis suggested that the WHOQOL-DIS module may best be analyzed as one general item together with a single domain with the other 12 items, which can also be used as four subscales for more detailed analysis.

Correlation analysis revealed good criterion validity between QOL, SAS, SDS, CIQ, and VAS. It was noticed that the correlation coefficients between the discrimination domain QOL and SDS/VAS were negative values with no statistical significance, which might be attributed to the following reasons: depression and self-rated health are very complicated inner feeling, however, the discrimination (social support) domain of the WHOQOL-DIS is mainly related to factors in the outer environment.^48,49

Our study reported good item–domain correlations, which suggested a high level of convergent validity, except for the general item of the WHOQOL-DIS, which might be related to its limited variability induced by a floor effect. WHOQOL-BREF domains and WHOQOL-DIS scores showed the predicted pattern among a priori known groups. Qiu et al.⁵⁰ and Putzke et al.⁵¹ reported results similar to our study, i.e. the female patients with subacute or chronic SCI had higher QOL than the males. This study showed that age was not a negative factor in the QOL of people with SCI, as a study in Australia had also found,⁵² but the previous studies in China found that age was a relevant factor,^25,26 Furthermore, being unemployed was associated with lower QOL scores in people with SCI in the US and in urban residents in China.^51,53 In contrast with this study, having less education was a predictor of lower QOL scores in those two studies.^51,53

This study had a few limitations to acknowledge. First, our participants were mainly from Shanghai. This asymmetric region distribution indicated that the study persons might not be fully representative. In other words, more data from people with SCI from other provinces in China should be collected to conclusively establish reliability. Second, survey compliance was very good, which could be related to the following facts: (1) the study was performed during the inpatient rehabilitation training period, and the participants were given enough time to complete the survey; (2) our participants cherished this free training opportunity (with all costs being paid by the Shanghai Disabled Persons’ Federation, a semi-government organization) given the background of there being very limited SIBR training resources in Mainland China. There would be expected missing values for research in larger or more demographically diverse communities. In particular, the percentage of missing value for item 21 (sex) might be over 30%.^25,54 Third, regarding the known-groups validity, a control group of non-SCI participants would have represented a more apt comparison than comparisons across demographic variables. Finally, inter-rater reliability was not performed in this study.

Conclusions

This study is the first reporting on the initial validity of the WHOQOL-BREF and WHOQOL-DIS module with people with SCI in Mainland China. We demonstrated that the WHOQOL Scales were reliable and valid instruments to measure the QOL of people with SCI in Mainland China. The health-related QOL data in people with SCI is important to help to improve their care. The WHOQOL Scales is based on a cross-cultural concept and can provide sufficient comparability across different countries and regions; thus, QOL surveillance for people with SCI in Mainland China based upon the WHOQOL Scales should be included in routine health care systems.

Disclaimer statements

Contributors None.

Conflicts of interest There are no conflicts of interest to declare.

Funding Statement

This work was supported by grants from the National Natural Science Foundation of China (71673052, 71774030), the Shanghai Pujiang Program of Shanghai Municipal Human Resources and Social Security Bureau (17PJC003), the 111 Project (Grant Number B16031) from Department of Education (US), and a major project of the National Social Science (No. 17ZDA078) from National Office for Philosophy and Social Sciences (CN).